Study On The Effect Of Different Raw Materials On Edible Quality Of Military Instant Rice

The military instant rice is developing rapidly,but the poor taste and gradation limit its development.To improve the military instant rice's taste and regenerative characteristics,and improve its nutrition at the same time,the research aims to select the optimal ratio of raw materials by the retrogradation value and study its edible quality by using japonica rice as main raw material,plant kuzuko powder,lotus root starch,sweet potato starch as supplementary material,and then making them mixed,granulated through two screw extrusion technology.The research also uses Scanning Electron Microscope(SEM),Differential Scanning Calorimetry(DSC)and X-ray diffraction(XRD)to make a thorough inquiry of the military instant rice's retrogradation mechanism.First,the single factor experiment which takes retrogradation value as main indicators uses japonica rice with different ratio of three kind of plant material(2%,4%,6%,8%,10%)to choose the right gradient of the orthogonal experiment.The gradient are:kuzuko powder 4%,6% and 8%,lotus root starch 2%,4% and 10%,sweet potato starch 2%,6% and 8%.Analyzing the correlation of the orthogonal experiment's retrogradation value and texture characteristics,the result indicates that the retrogradation value is positively correlated to degree of hardness and negatively correlated to viscous,elastic.At the same time,comparing the RVA characteristic values of the orthogonal experimental groups,then determining their eating quality.So the optimal solution of the orthogonal experiment should do better not only in retrogradation value,but have good taste according to texture and RVA.Second,analyzing four samples'(6% single extrusion blank control group,the optimal ratio of extruded rice,Northeast rice and instant rice sold on the market)organoleptic characteristics and physicochemical characteristics,comparing their tastes,the result shows:the optimal ratio of extruded rice's degree of gelatinization(BD),water solubility index(WSI),water absorption index(WAI)are max,BD is smaller.In terms of texture,the extruded rice's hardness,viscosity,chewiness are lower,its' elastic is lower than Northeast rice but higher than the instant rice sold on the market,the optimal ratio of extruded rice' hardness,viscosity,chewiness are lower than the extruded control group,but its' elastic is closer to the fresh rice.Inspect the appearance,the optimal ratio of extruded rice's smell,taste,palatability,cold rice texture are closer to the fresh rice.Other three samples are too different with the fresh rice in organoleptic evaluation.In comparison,the optimal ratio of extruded rice's taste is closer to the fresh rice.Thus it can be seen that the optimal ratio of extruded rice' edible quality is closer to the fresh rice.At last,the research discusses the military instant rice's retrogradation mechanism.Composite extruded rice(the military instant rice)has a more loose and porous structure and easier to be rehydrated compared with the original rice and the extruded control group.After extruding,rice starch structure has changed from type A crystal to type V crystal.The X-ray diffraction peak area and peak intensity of the composite extruded rice are weaker than those of the control group.Three kinds of rice recrystallization nucleation method is primary nucleation,extrusion reduces the recrystallization growth rate and nucleation rate,composite extrusion rice crystal growth rate is higher than the extrusion control group.These indicate that the extrusion can inhibit the regeneration,and the composite extruded rice's inhibiting retrogradation characteristics are superior than the extrusion control group.